In an OFDM (Orthogonal Frequency Division Multiplex) based wireless communication system, such as IEEE 802.16m the uplink power control can be an issue for the overall system performance and for battery life of a Mobile Station (MS). In the uplink direction multiple orthogonal resource units or sub-carriers may be defined in the frequency domain based on OFDM as may be described in IEEE 802.16m.
In the document IEEE 802.16m, System Description Document, “IEEE 802.16 Broadband Wireless Access Working Group”, 2008-12-12, a system description may be provided for a further development of the IEEE 802.16m System Description.
The document IEEE 802.16e-2005 and IEEE 802.16-2004, “IEEE Standard for Local and Metropolitan Area Networks—Part 16: Air interface for fixed broadband wireless access systems, Amendment 2: Physical and Medium Access Control Layers for Combined Fixed and Mobile Operation in Licensed Bands and Corrigendum 1,” Feb. 28, 2006 may describe supporting subscriber stations moving at vehicular speeds and thereby may specify a system for combined fixed and mobile wireless access.
The document 3GPP TSG RAN1 #44, R1-060401, “Interference mitigation via power control and FDM resource allocation and UE alignment for E-UTRA uplink and TP”, Agenda item 13.2.3.6, Motorola, February 13-Feb. 17, 2006, Denver, USA, may disclose a fractional power control scheme with FDM resource allocation for E-UTRA uplink and simulation results.
The document 3GPP TSG RAN WG1 #46bis, R1-062861, “Uplink power control for E-UTRA (Evolved UMTS (Universal Mobile Telecommunications System) Terrestrial Radio Access)”, Agenda item 6.8, Oct. 9-13, 2006, Seoul, Korea, may describe a power control mechanism controlling the power spectral density.
The document 3GPP TSG RA1 WG1#44 meeting, R1-060297, “Uplink power Control”, Agenda item 13.2.3.4, Nokia, 13-17 February, 2006, Denver, USA, may disclose deriving an initial transmission power according to a path loss measurement from a downlink pilot channel during a random access phase.
The document 3GPP TSG RAN WG1 #47bis, R1-070251, “Power control of uplink shared data channel”, LG Electronics, Agenda item 6.12, Jan. 15-19, 2007, Sorrento, Italy, may describe a modified fractional power control scheme.
The document 3GPP TSG-RAN WG1 #48-bis, R1-071716, “Fractional power control using pilot power ratio measurements for the E-UTRA uplink”, Agenda item 7.6, Alcatel-Lucent, Mar. 26-30, 2007, St. Julians, Malta, may describe open loop fractional power control using the path loss difference between serving cell and a strongest neighbour cell.
The document 3GPP TSG RAN WG1 meeting #47, R1-063231, “Uplink power control for E-UTRA: Optimizing the trade-off between cell-edge and cell-average throughputs”, Agenda item 6.9, Texas Instruments, Nov. 6-10, 2006, Riga, Latvia, may disclose a base line power control method.
There may be a need to provide a more efficient power control.